Add support for OpFMod
Add support for OpFMod

Bug: b/126873455
Test: dEQP-VK.glsl.operator.common_functions.mod.*
Change-Id: I7f261e7bd4dda72b18594cd7e2ee7044bc60466b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/27369
Tested-by: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>
Presubmit-Ready: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Kokoro-Presubmit: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader